Principal Investigator / Author(s): Hoffmann, Michael R

Contract Number: A6-185-32

Interception of cloudwater by forests in the Sierra Nevada may contribute significantly to acid deposition in the region. Cloudwater sampled in Sequoia National Park had pH values ranging from 4.4 to 5.7. The advance of cold fronts into the Park appears to lead to higher aerosol and gas phase concentrations than are seen under normal mountain/valley circulations, producing higher cloudwater concentrations than might otherwise be expected. Estimates of annual deposition rates of NO3- SO42-, NH4+and H- due to cloudwater impaction are comparable to those measured in precipitation.

For questions regarding this research project, including available data and progress status, contact:
Heather Choi
at (916) 322-3893